An assembly for reducing oxidation of a semiconductor device comprises a holding device for securing the semiconductor device to a platform. The holding device includes at least one opening for providing access by a bonding tool to bonding areas where the semiconductor device is to be bonded. A slidable cover covers the holding device and has a slot for providing access by the bonding tool to the bonding areas through the slot. A guiding device is positioned on the slidable cover and is coupled to a pusher which is operative to push the slidable cover to move along a first axis. The pusher is further guided by the guiding device to move relative to the slidable cover along a second axis which is perpendicular to the first axis without pushing the slidable cover to move in the second axis.